Describe RanjithaKumar/HomeWork1 here.
For Configuration 1, I had problems with keeping the background black while maintaining strong light from the forehead down to the chin. I added one additional parameter to the spotlight, "float conedeltaangle", which helped me control the angle at which the spotlight intesity began to fall off. I used the nose shadows to help me judge the relationship between the y and z components of the light position and used a very narrow cone angle.
Configuration 2 was pretty straightforward: I just aimed an area light directly to the face from the right.
Configruation 3 was also pretty straightforward: I used a very wide cone angle to illuminate the whole background, and a very small area light from the right to highlight the left side of the face softly.
For Configuration 4, it was extremely useful to place one light at a time and make sure that it matched the corresponding given image. I used spotlights for the background and accent lights and area lights for the fill and main lights. I actually first tried using a spotlight for the main light, but I found that I couldn't get the soft shadows on the left side of the face: so I had to use an area light to achieve this effect.
To expedite the process of testing, I first rendered images at 100X100 resolution, with 1 sample per each image output pixel, and 1 sample per each area light source. I magnified these preliminary images in Photoshop and checked if my camera position and general light positions were correct. Then, I rendered images at 200X200 resolution, and 2 samples per each output pixel and area light source to check if the subtle shadows and highlights matched up.